Operating speed

The speed at which the computer’s processor can execute commands, usually expressed in megahertz (MHz), such as 33 MHz. See also Megahertz.

Operating system

A collection of programs that manages a computer’s operations, such as interpreting input, managing files, and reading and writing data to disk. The operating system (such as MS-DOS, OS/2, or UNIX) provides the foundation for the other programs you use and controls the usage of the hardware resources.

Option card

A circuit board you can install inside the computer to provide additional capabilities, such as a modem or an additional I/O port. Option cards plug directly into the special option slots so you do not have to alter a computer’s circuitry to enhance your system. See also Bus.

OS/2

Operating System /2. The enhanced operating system developed jointly by Microsoft and IBM that provides protected mode processing and multitasking capabilities. See also DOS, MS-DOS,and Operating system.

Parallel

The type of interface that transmits all the bits in a byte of data simultaneously over separate wires in a cable. See also Interface and Serial.

16 Glossary